Unit 2.1 Inside the Atom

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Introduction

Every Substance in world are made up of atoms.

An atom is smallest uncharged that take place in chemical reaction but atoms are still made out of smaller particles call subatomic particles.

At the centre of an atom the is a tiny nucleus. The nucleus is made up of protons and neutrons (general name: nucleon). The number of the nucleons there are is called nucleon number or mass number

Outside the nucleus, there electrons which move around in areas which call electron shells or energy levels. The shells are certain distance from the nucleus and there can several shell further away form the nucleus. Each of these can hold a certain number of electrons

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The three subatomic particle have different charges and properties seen in table above.

Most the mass of an atom is in nucleus and it neutral charge as protons and electron cancel themselves out

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The Importance of proton number

The number of proton in the nucleus is all proton number or atomic number. Every atom of same element has same proton number. The perodic table is arrange by these proton number and that why they are so important

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Refrence

pg 22-23